This multi-year research project initially built upon a few worrisome empirical observations regarding the 2000s from Annual Crime Reports by the Supreme Prosecutors’ Office of Korea. First, the number of regulatory crimes has exceeded that of since 1982. In the 2000s, despite a slow average growth rate of 1.5%, regulatory crimes still accounted for as much as 60% to the total. Second, the number of conventional (or customary) crimes, in contrast, increased relatively fast at 2.6%, and increased more rapidly in the last 3 years. Third, the number of violent crimes, in particular, increased much faster, with an average growth rate over the 2000s of 4.4%, and, for the last 3 years, the average growth rate for violent crimes even reached 7.2%. Finally, according to a different data source, there was fast growth of ex-convicts in Korea at least for the past decade.

Over the years I have been convinced that overcriminalization was the major cause of this troubling picture. The purpose of this study, therefore, is to investigate the main hypothesis that introducing too many regulations and subsequently overcriminalizing the regulatory violations have distorted the entire system of criminal justice. Also, I intend to show that the disproportionate focus on enforcing these regulatory crimes has contributed significantly to the irregularities and has imposed a serious opportunity cost upon the Korean economy.

Overcriminalization is defined as a phenomenon that the marginal social cost of an additional penal clause exceeds the marginal benefit. From the law and economics perspectives, criminal punishment becomes an appropriate deterrent-institution only when an act with a clear intention or mens rea is faced with the two main hurdles which the traditional tort law cannot overcome, ‘incomplete compensation’ and ‘extended harm.’ As the most basic proposition, an act becomes a crime ‘only when’ the level of culpability, which is determined by total harm and mens rea, exceeds a certain threshold. In this study I thus have distinguished harmful acts into about ten meaningfully different groups and have determined their culpability. In a nutshell, I claim that overcriminalization takes place unless these considerations are strictly executed.

Overcriminalization imposes substantial social costs. The social costs are at least three-fold. The first is production of too many ex-convicts weakening the intended desirable functions of criminal punishment. The second is distortion in the incentives of law enforcers usually associated with their unconstrained discretion. Also, severe inefficiency in allocating enforcement resources is the third social cost. In the process of discussing these issues, I have critically emphasized the nexus among regulations, overcriminalization of their violations, and consequent overenforcement.

More specifically, in this study I have endeavored to show several facets of empirical evidence. First, the growth of ex-convicts in Korea most probably was faster than in other countries. Second, the surge in the ex-convicts stock in Korea was driven mainly by regulatory criminals, which can be interpreted as an outcome of overcriminalization of regulatory violations. Third, the choice of which case to prosecute largely determines the composition of newly added ex-convicts. Given all these results, studies on the prosecuting pattern appear to be shedding critical implications for the criminal justice policy in Korea. Fourth, it will be very intriguing to know the unintended consequences (or tradeoffs) of disproportionate prosecutory focus on regulatory crimes, and I have indeed empirically shown that the opportunity cost seems fairly high. Fifth, my empirical case study regarding the Korea Fair Trade Act, utilizing various proxies for harm size and mens rea, have revealed that the Act is currently being overly criminalized.

I admit both data constraints and a certain level of uncertainty concerning the empirical methodologies. Nonetheless, given the absence of preceding literature especially on the last empirical investigation above, I hope that this study will trigger future analyses with more rigor. The final question then comes down to this: What should be done? Commentators sometimes claim that not until ordinary citizens (or median voters) clearly understand these issues can a country contain overcriminalization. It may be a correct statement, but that will take a tremendous amount of time. I believe that there exist independent or supplementary resolutions which must be urgently taken by the legislature, administration, and judiciary. Thus, at the final part of this study, I have provided the outline regarding the roles of the three branches of the Korean government. Nevertheless, the precise road map of prescription policies appears to be so complicated that I will leave detailed discussions for another occasion.